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Biomedical subjects

J Sirot

Publications and source records attributed to J Sirot.

At least 127 records · Page 7Linked to original sources
PubMedDate not supplied

Treatment of a meningitis due to an Enterobacter aerogenes producing a derepressed cephalosporinase and a Klebsiella pneumoniae producing an extended-spectrum beta-lactamase.

A case of nosocomial meningitis due to a Klebsiella pneumoniae producing a CAZ-5 extended-spectrum beta-lactamase and an Enterobacter aerogenes producing a derepressed cephalosporinase is reported. The intrathecal catheter incriminated was removed and a treatment with ceftazidime (4 g/24 h) and amikacin (1.5 g/24 h) was started. After 24 h ceftazidime was replaced by imipenem (2 then 4 g/24 h). This treatment failed to obtain cerebrospinal fluid sterilization; therefore the imipenem dosage was increased to 8 g/24 h and two intrathecal infusions of amikacin (50 mg) were carried out. Thereafter the patient recovered.

Adult↗
PubMedDate not supplied

Susceptibility of new beta-lactams to the expanded-spectrum beta-lactamase CTX-1.

Forty-three clinical isolates of enterobacteria were selected for the production of the new plasmid-mediated expanded-spectrum beta-lactamase CTX-1. The geometric means of MICs were ranged as follows: ticarcillin, greater than 4096 mg/l; ticarcillin + clavulanic acid (2 mg/l), 64-87 mg/l; LY 163892, 8.0-69.1 mg/l; cefotaxime, 5.7-26.4 mg/l; temocillin, 8.0-21.8 mg/l; Ro 158074, 4.0-18.7 mg/l aztreonam, 1.0-14.4 mg/l and BMY 28142, 1.4-2.8 mg/l. Moxalactam, imipenem and CM 40876 were resistant to hydrolysis and MICs were lower than 2.0 mg/l. A high protective effect on cefotaxime (MIC less than or equal to 0.5 mg/l) was obtained by sulbactam (4 mg/l). Escherichia coli transconjugants from each species showed similar levels of MICs.

Anti-Bacterial Agents↗
PubMedDate not supplied

Pharmacokinetics of cefotaxime and its desacetyl metabolite in plasma and in cerebrospinal fluid.

The aim of the study was to investigate the pharmacokinetic modelling of Cefotaxime (CTX) and its main metabolite Desacetyl Cefotaxime (DCTX) which has a less antibacterial activity than the CTX. After intravenous administration of 1g of CTX to 26 patients, the plasma concentrations determined by HPLC showed that the pharmacokinetics of CTX and transformation to DCTX can be described with an open five-compartment model. The implications of this are discussed from the clinical point of view.

Adolescent↗
PubMedDate not supplied

Decreased susceptibility to extended-spectrum cephalosporins of a penicillin-susceptible Streptococcus pneumoniae in meningitis.

A 69-year-old woman was admitted to the hospital with meningitis due to Streptococcus pneumoniae. The strain was susceptible to penicillin but intermediate to cefotaxime. In Europe the decrease of susceptibility generally pertains more to penicillin than to cefotaxime. Such a strain is perhaps a forewarning of the existence of high-level cephalosporin-resistant strains. Despite the possible detection of the resistance by oxacillin disk, it underlines the need to determine the MICs of different beta-lactams without delay and to choose the most efficient treatment.

Aged↗
PubMedDate not supplied

Klebsiella pneumoniae and other Enterobacteriaceae producing novel plasmid-mediated beta-lactamases markedly active against third-generation cephalosporins: epidemiologic studies.

Analysis of the enzymes produced by clinical isolates of multiresistant Klebsiella pneumoniae from hospitals in France revealed two novel broad-spectrum beta-lactamases. The first, characterized by an isoelectric point of 6.3 and a high hydrolytic activity on cefotaxime, is designated CTX-1. This beta-lactamase was encoded by a 95-kilobase plasmid (incompatibility group 7M) and cotransferred with resistance to tetracyclines, sulfonamides, and aminoglycosides (AAC [6']-IV). From 1984 to June 1987, 490 CTX-1-producing strains of Enterobacteriaceae were isolated. The second plasmid-mediated beta-lactamase (CAZ-1) was isolated in 1987 from three K. pneumoniae strains more resistant to ceftazidime than to other third-generation cephalosporins. This broad-spectrum beta-lactamase differed from CTX-1 by its isoelectric point--close to 5.6--and its high hydrolytic activity on ceftazidime and was encoded by a 150-kilobase plasmid. It was demonstrated that these expanded-spectrum beta-lactamases are TEM derivatives.

Cephalosporins↗
PubMedDate not supplied

Interactions of new plasmid-mediated beta-lactamases with third-generation cephalosporins.

The kinetic constants of three recently identified plasmid-mediated beta-lactamases--SHV-2, CTX-1, and CAZ-1--markedly active against third-generation cephalosporins were analyzed in comparison with three better-characterized beta-lactamases--two plasmid-mediated enzymes, TEM-2 and PIT-2/SHV-1, and R-30, a beta-lactamase from Klebsiella oxytoca that has few similarities to the newer enzymes. All of these enzymes are synthesized constitutively, demonstrate efficient hydrolysis of penicillins, are highly susceptible to the action of clavulanic acid and sulbactam, and have no detectable activity against the cephamycins and imipenem. With the methoxyimino cephalosporins, including those of the third generation, the rates of hydrolysis observed for the SHV-2, CTX-1, and CAZ-1 enzymes are high and show no relation to those observed for the other presently known beta-lactamases. Structure-activity relations suggest that the oxime substituent of these cephalosporins is a major structural factor in the catalytic process observed with the three new beta-lactamases.

Cephalosporins↗
PubMedDate not supplied

Human and animal epidemic of Yersinia enterocolitica O:9, 1989-1997, Auvergne, France.

Yersinia enterocolitica O:9 infections were reported in Auvergne in 1988 to 1989, while brucellosis due to Brucella abortus was almost eliminated. The serologic cross-reactions between the two bacteria complicated the diagnosis of brucellosis cases. In 1996, human cases of Yersinia enterocolitica O:9 infection were detected, with a peak incidence of 12 cases. Veterinary surveillance could have predicted the emergence of this disease in humans.

Animals↗